a(n) = 7*(n+1)*binomial(n+3,7).

Terms

a(0) =35a(1) =336a(2) =1764a(3) =6720a(4) =20790a(5) =55440a(6) =132132a(7) =288288a(8) =585585a(9) =1121120a(10) =2042040a(11) =3564288a(12) =5996172a(13) =9767520a(14) =15465240a(15) =23876160a(16) =36038079a(17) =53300016a(18) =77392700a(19) =110510400a(20) =155405250a(21) =215495280a(22) =294987420a(23) =399016800a(24) =533803725a(25) =706829760a(26) =927034416a(27) =1205033984a(28) =1553364120